docs: def _get_stddevs(self, C, sites, pga1100, sigma_pga, stddev_types):
          """
          Returns the standard deviations as described in the "ALEATORY
          UNCERTAINTY MODEL" section of the paper. Equations 13 to 19, pages 147
          to 151
          """
          std_intra = self._compute_intra_event_std(C,
                                                    sites.vs30,
                                                    pga1100,
                                                    sigma_pga)
  
          std_inter = C['t_lny'] * np.ones_like(sites.vs30)
          stddevs = []
          for stddev_type in stddev_types:
              assert stddev_type in self.DEFINED_FOR_STANDARD_DEVIATION_TYPES
              if stddev_type == const.StdDev.TOTAL:
                  stddevs.append(self._get_total_sigma(C, std_intra, std_inter))
              elif stddev_type == const.StdDev.INTRA_EVENT:
                  stddevs.append(std_intra)
              elif stddev_type == const.StdDev.INTER_EVENT:
                  stddevs.append(std_inter)
          return stddevs